I'd imagine that it is satisfying, yes. But I think you may be underestimating how little other people will value your time in asking for help using that software. I have a colleague that maintains a popular open source project, and he spends a ridiculous amount of time answering questions about problems they're having, and very often those problems don't have anything to do with the software he's written, but the competence of the questioner. I had been considering developing a package, perhaps paid for with grant money, but the long term commitment that comes with it has scared me off.